Electric heater terminal construction



Aug. 13, 1935. R. a. MARSHALL ELECTRIC HEATER TERMINAL CONSTRUCTION Original Filed April 23,11932 2 Sheets-Sheet 1' R. B. MARSHALL ELECTRIC HEATER TERMINAL CONSTRUCTION Aug. 13, 1935.

Original Filed 'April 25, 1932 2 Sheets-Sheet 2 VE fi'c'iard Z? Waruiaff.

Patented Aug. 13, 1935 if?"UNITEDSTAT S ELECTRIC 2,010,953 HEATER TERMINAL CONSTRUCTION Richard 3; Marshall, Grosse Pointe, Mich" assignor to Electromastcr 1110., Detroit, Mich., a

corporation of' Michigan Original application April 23; 1932, Serial No. 607,022. Divided and this application January :15, 1934 Serial N0. 706,603 V 7 claims (01. 173-259) This invention relatesin general to improvements in heating element assemblies such as assembly.

. Mo re specifically, the present invention con stitutes a division of my copending application entitled I-Ieating element assembly, Serial No.

1501022 filed April 23, 1932, issued as Patent "1375558, on Oct. 2, 1934, and is directed to the features of the constructionof ent em i a ir i It is, therefore, a prim'ary object of the present ention toprovide improved terminals for the 'h a ting element; these terminals *beingso arranged that they are removed from the heating z'onef ja'nd's'o constructed thatthey willnot heat the heating eler .p atthe points where electrical connections are 'niadethereto.

In accordance with the general features of this invention, it is; proposed to provide a refractory member forsupporting the heating "element; this member being supported within a ring member alndfheld out of 'cbntact with the ring member ring member. In this instance, four padshave been used although a less orgrealte'r number may be-used, if desired. The ring'member is likewisefsupported out-'0: contact with the cooking table by similar pads.- on the ring member, in

"this' insta-nce," three 'in" number. A radiating plateis disposed below the refractory. and ring members; this plate being held in positionby a two-point suspension from the refractory member. Further; the terminals for the heating element are disposed below the reflector-plate and are provided with radiators to eliminate "heating of the terminals at the points' where -'electrical connections are "made. i The above.

arrangement is advantageous in that the various 7 elements composing the completeassembly are so arranged as to present minimum contactsur- "faces; therebymate'zially lessening the conduction "or eat energy into channels where it will serve useful purpose. l The entire organization efff'i ects afheatingelement assemblywhich is, more efiicient-than those heretofore used. -'-C)tlie r objects and features of this invention will mdreauny appear from the following detailed I' iATENT'loFFICE description taken in connection with the accompanying drawings which illustrate a single embodiment thereof, and in which Figure l is a plan View of the top of a cooking table embracing a heating element assembly embodying the featuresof this invention;

Figure 2 is a plan view looking at the heating element assembly frombelow, certain portions being cut away to more clearly disclose the relationship between the various elements thereof; Figure 3 is an enlarged fragmentary vertical section through the cooking table topand the heating element assembly, the terminals for the heating element being shown in'elevation, taken substantially on line IIIIII of Figure l;

Figure 4 is an enlarged vertical'section through the heating element assembly to show the manner of supporting the refractory member, taken substantially on line IVIV of Figure 2; Figure 5 is an enlarged vertical fragmentary section showing the manner in which the refractory member is secured against removal from the associated supporting ring, taken substantially on line V-V of Figure 2; and

Figure 6 is an enlarged fragmentary view in elevation .of the supporting ring member showing the pads for holdingthe ring member spaced relative to the top of the cooking table. i 7

As shown on the drawings: The present invention is illustrated erably being embodied in'a heating element assembly such as described in my co-pending application, but may obviously be used with equal facility in other structures. The entire assembly is'mounted, as shown in Figure 1, in a top H] of a cooking table which is of the usual construction and which 'forms a part of an electric stove, range, -or other cooking appliance. The cooking table-is provided with "the usual openings as shown at H for receiving the heating element 4 assembly.

' Disposed within. the opening Lin the top of the cooking table is a ring member l2' which may be constructed of any suitable material,.although I have found thatlcast iron is particularly adapted for this purpose. The upper end of this ring member is deflected outwardly so as to form an annul'ar'flange I3. The ring member 12 is sup- :ported imposition with the flange i 3 spaced above as prefthe top ofthe cooking tableby means of a plurality o'f pads M which are integrally formed withand project from the lower surface of the flange. 1 It is contemplated that the ring lzrmay be supported at any desired number of. points around the flange l2, but in order-to reduce the 55 'neath each of the lips 2| isan opening 5 one of the grooves.

contact area between the ring [2 and the top of the cooking table to .a minimum, it is preferable that there should be not more than three points of supports. By providing three points of support, thering i2 is effectively retained against tilting movement and at the same time. there is a minimum surface in contact with the top of the cooking table.

The lower edge of the ring I2 is provided with a plurality of inwardly extending arms l5 which are uniformly spaced around the ring. The upper surface of each arm is provided with an integrally formed pad iii. The arms l5 are preferably interconnected by a web H which is integrally formed with the arms and lower edge of the ring 52, thereby strengthening this portion of the ring. 4

A refractory member El composed of any suitable highly refractory material is disposed with in the ring I2 and supported upon the pads It so that it is spaced from the arms Q5 of the ring. It will be noted that the refractory member H is of less diameter than the internal diameter of the ring 52 so that the only surface contact with any portion of the ring is at the pads it, a relatively small contact surface thereby being provided through which heat may be conducted from the refractory member to the ring. The upper surface of the refractory member Il as shown in Figure l, is provided with a pair of spirally arranged parallel grooves l8 and !9, the convolutions of one groove being alternately disposed relative to the other groove. Each groove begins at a point adjacent the central portion of the refractory element li and is spiraled out wardly, the outer ends of the grooves being terminated at opposite sides of the refractory element. Each of the grooves l8 and i9 containsa coil of suitable resistance wire 29 which is held within the grooves by means of spaced lips 2! formed on the groove walls and overhanging the heating elements disposed in the grooves. Directly be- 22 which extends through the body of the refractory member H and forms a passageway extending from the lower surface of the refractory member into These passageways enable a circulation of air from below the refractory member in an upward direction through the refractory member and toward the upper surface thereof, thereby keeping the refractorymember cool and carrying the heat energy toward the cooking utensil which would be disposed over the refractory member during the cooking operation.

The refractory member ll is retained against removal from the ring l2 and in contact with the pads it of the arm l5 by means of outwardly disposed clips 23, one of which is shown in Figure 5. The clips 23 extend at one end through a cut-out portion 24 in the ring 12. The inner end of the clip 23 is secured against the undersurface of the refractory member l'l by means of a bolt 25 and nut 26.

The bolt 25 also serves as a support for a reflector plate 21, this plate being apertured to receive the screw 25 and held against the nuts 2t by means of a second set of nuts 28. It will be observed that with this arrangement, the reflector plate is spaced belowthe refractory member and is of such size as to extend outwardly over the lower edge of the ring i2. Here, again, it will be observed, the reflector plate 2'i is suspendedfrom the refractory member at two points, thereby providing a minimum surface contact between the ;refractory member andthe plate, with the result that direct conduction of heat is materially lessened.

The inner ends of the spiraled heating element are brought out to a central terminal A and the outer ends of the heating element are respectively connected to terminals B and C. Since each of the terminals A, B and C is similarly constructed, only one will be described.

Referring to Figure 3, each terminal comprises a bolt 29 which extends through the refractory member H and is securely held against removal therefrom by means of a nut 30 securely tightened against the undersurface of the refractory member. The bolt 29 extends through a suitable aperture 3! which is provided in the reflector plate 21. Spaced below the reflector plate 21, so as to be removed from the heating zone, .a metallic disc 3! surrounds the bolt 29 and is securely held against axial movement by means of nuts 32 and 33 which are disposed on either side of the disc and tightened thereagainst. Between the spaced nuts 30 and 32 is a nut 34 which may be actuated to clamp the terminal connections from the inner ends of the heating elements between a plurality of washers 35 when the nut 34 is actuated so as to move toward the nut 32. Line connection to the terminals may be made by inserting a line wire between a washer 35 and the nut 33, the connection being securely fastened by tightening a nut 31 which is also on the bolt 29.

It will be observed that, with the foregoing terminal arrangement, the electrical connections on each terminal are disposed on each side of the disc 3|. This disc substantially increases the radiating surface of the terminal and serves to keep the terminal. cool, thereby obviating the possibility of its becoming hot by virtue of the electrical connections thereto.

From the foregoing, it willbe apparent that this invention provides a novel terminal construction that is particularly adapted for use in connection with a heating unit, and terminals which are disposed outside of the heat zone and. are provided with radiators for keeping them cool at all times, whereby the heating unit may be more efficiently operated.

Now, it is, of course, to be understood that although I have described in detail the preferred embodiment of my invention, the invention is not to be thus limited but only insofar as defined by the scope and spirit of the appended claims.

I claim as my invention:

1. In a heating element assembly, a terminal connection comprising a threaded member, a disc secured to said member between the ends thereof and of such construction as to form a radiator having opposed radiating surfaces, means to secure said disc relative to said member, said disc extending outwardly beyond its securing means a substantial distance, a clamp connection on one side of said disc for connecting the heating element to said terminal, and a clamp connection on the other side of said disc for connecting a conductor from a source of supply to said terminal.

2. In a heater having an insulating element, a terminal structure comprising a bolt solely supported at its head end in said element and projecting normal thereto, a heat conducting member having a relatively large radiating surface, said member being secured to said bolt and spaced from said element, and means on either side of said member clampingly associated therewith for securing conductors to said terminal.

conducting material of such diameter as to present a large radiating surface, said disc being secured to said bolt and spaced from said element, and means on either side of said disc clampingly associated therewith for securing conductors to said terminal.

4. In a heater having an insulating element,

a terminal structure comprising a, bolt secured at its head end in said element and projecting normal thereto, arelatively thin disc of heat conducting material of such diameter as to expose parallel surfaces of substantial radiating area, said disc being secured at its central portion to the bolt in spaced relation to its ends with the planes of its surfaces normal to the bolt, and means on either side of said disc clampingly associated therewith for securing conductors to said terminal.

-5. As an article of manufacture, a terminal assembly comprising a bolt having a threaded stem and a head atone end, a nut threaded on said stem to cooperate with said head-to rigidly secure the bolt to a supporting structure, a thin disc of heat conducting material having a central opening to receive said stem, nuts on said stem clampingly engaging opposite sides of the disc, the planes of the disc surfaces being normal to the stem axis, and extending a substantial amount beyond the outer margins of the last mentioned nuts and other nuts on the stem respectively cooperating with the disc holding nuts for securing a wire connection to said terminal on each side of said disc.

6. As an article of manufacture, a terminal assembly comprising an elongated threaded member, means at one end of said member to rigidly secure the same to a supporting structure,

a thin disc secured to said member with the planes of its parallel surfaces normal to the axis of said member, and pairs of nuts respectively disposed on either side of said disc, whereby conductors may be secured to said terminal, the disc extending outwardly a substantial distance beyond the outer margins of said nuts, whereby relatively large radiating surfaces are exposed.

7. Terminal means comprising a bolt having its stem threaded to a point adjacent its head, a nut threaded on the stem adapted to cooperate with said head to secure the bolt to a supporting structure, a relatively thin disc of heat conducting material having a central opening for receiving the stem, nutsthreaded on the stem on either side of the disc and tightly engaging the disc, the disc being of such diameter as to extend a substantial amount beyond the outer margins of said nuts, whereby relatively large opposed radiating surfaces are exposed, said disc being so located on the stem as to leave substantial threaded portions of said stem extending outwardly from the last mentioned nuts, and nuts on said threaded portions actuatable into engagement with the disc holding nuts for securing a wire connection on each side of the disc without disturbing its securing nuts.

RICHARDB. MARSHALL. 

